Cloud Point Extraction and Flame Atomic Absorption Spectrometric Determination of Lead, Cadmium and Palladium in Some Food and Biological Samples

The proposed method is based on the complexation of the Pb2+, Cd2+ and Pd2+ ions with 3-(1-(1-H-Indol-3-Yl)-3-phenylallyl)-1H-indole (IPAI) at pH 8.0 in the presence of Triton X-114. The phase separation occured when micellar solution was heated at 55 degrees C. The surfactant-rich phase, diluted to 0.5 mL via 1.0 mol L-1 nitric acid in methanol was directly introduced into the nebulizer of the flame atomic absorption spectrometry (FAAS). Influence of variables such as pH, amount of ligand and Triton X-114, heating time and temperature were evaluated and optimized. The optimized enhancement factors for Pb2+, Cd2+ and Pd2+ ions were 22, 33 and 23, respectively and the detection limit (DLs) was between of 1.6-2.6 mu gL(-1). The relative standard deviation (RSD) of each ion was found to be less than 4.6% at 100 mu gL(-1). In addition, the calibration graphs were linear in the range of 0.01-0.22 mu g mL(-1) for Cd2+ ion, 0.018-0.26 mu g mL(-1) for Pb2+ ion and 0.020.27 mu g mL(-1) for Pd2+ ion with the correlation coefficients in the range of 0.995-0.999.